A so-called “dark field” inspection was proposed in U.S. Pat. Nos. 4,630,276 and 4,740,708. The inspection is said to be a dark-field inspection since an absence of a defect is expressed by a dark image. In the absence of any defect, the incident beam is reflected. Emphasis is laid on the light scattered by the inspected surface of the semiconductor wafer. In the case when a defect is present, a portion of the incident beam is scattered. The scattered photons are then captured in order to infer therefrom information relating to the defects.
The applicants have identified a need for a compact inspection machine with high accuracy, not very sensitive to the direction of the defects, having a low manufacturing cost and a short inspection time.
The invention will improve the situation.